A plastic-bonded explosive, also called a PBX or a polymer-bonded explosive, generally contains an energetic “oxidizer” homogeneously dispersed in a matrix of a synthetic thermoset polymer or a “binder matrix”. In this form, the PBXs exhibit “insensitive munitions” (IM) properties, which render them capable of withstanding sympathetic detonation as a result of mechanical shocks, fire, electrostatic discharge, and impact by shrapnel, yet are still capable of high-order detonation per design intent. These PBXs are referred to as IM-based explosives. Conventional PBXs typically comprise oxidizers such as HMX (or “high melting point explosive”), chemically known as cyclotetramethylene tetranitramine, RDX (or “royal demolition explosive”), chemically known as cyclotrimethylene trinitramine, C1-20, chemically known as 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, or combinations thereof.
However, conventional PBXs suffer from several shortcomings. Conventional PBXs often suffer from short service life due to mechanical, thermal and/or ballistic degradation caused by exposure to extreme environments, such as high temperature, moisture, or a synergistic effect of both over time. Many conventional PBXs do not exhibit robust performance post-exposure beyond twenty years. In addition, many PBXs contain plasticizers, which are added to the explosive formulation as a processing aid. Over time, these plasticizers can migrate or diffuse from within the binder matrix to the surface of the PBX or to other locations within the binder matrix, thus compromising explosive properties. This diffusion results in increased hardness of the explosive charge, noticeable shrinkage, and in extreme cases noticeable degradation in mechanical properties, leading to collapse of the charge as a result of loss of binder support (catastrophic failure).
In addition, as warfare technology advances, there is a continuing drive to develop PBXs that offer significant explosive output and superior brisance compared to existing explosives. This translates into PBXs that have far superior detonation velocity coupled with far superior detonation pressure compared to conventional PBXs. With this drive for higher energy density has come the desire for PBXs with improved IM properties that prevent or minimize the danger that the PBXs will detonate accidentally upon inadvertent shock, impact, electrostatic discharge, and the like.
Accordingly, it is desirable to provide PBXs with improved explosive output and improved IM properties. In addition, it is desirable to provide PBXs with improved service life. It is also desirable to provide PBXs that offer minimal or no plasticizer migration. In addition, it is desirable to provide methods for fabricating such PBXs. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.